Decorated plastic sheeting



NOV. 21, 1933. R DICKSQN 1,936,351

DECORATED PLASTIC SHEETING Filed Dec. 12, 1931 Fig.1

1P rz-F. 0/ m INVENTOR.

4 7 .1 or ATTORNEY Patented Nov. 21, 1933 r t l-UNITED STATES PATENT @FFME I 1,936,851 DECORATED PLASTIC SHEETING Robert F. Dickson,L eominster, Mass, assignor to Dupont Viscoloid Company, Wilmington, DeL, a corporation of Delaware Application December 12, 1931 Serial No. 580,722

' 2 Claims. (01. 18-57) This invention relates to decorated plastic cross sectional View and Figure 2 a face view, both sheeting, for example cellulose ester (e. g cellulose somewhat conventional and exaggerated, of a nitrate or acetate) or cellulose ether plastic sheetsheet in accordance with my invention. ing, and more particularly to the finishing of I have found that a finish which will harmonize 5 sheeting for use in the wood heel covering trade. with grained leather and textile fabrics and It is of particular virtue in the production of which is highly desirable for use in the wood shoe plastic sheeting having finishes which harmonize heel covering trade may be produced on a plas- With grained shoe leathers or textile fabrics. tic sheet preferably of cellulose ester or ether It has heretofore been proposed to make imitaby a sheeting or cutting operation. In general actions of grained leathers on plastic sheeting by cordance with my invention the cellulose derivaembossing the cellulose plastic sheet, either betive plastic y b p p With any of tht tween plates one of which contains the design, regular compositions known to the plastic sheet- .or passing the sheet between embossing rolls'one ing art, for use in the W Shoe heel Covering of which is usually heated. The embossing is t ade. It y b Colored to match the leather usually done on thestandard sized commercial or textile of t S e a y ay not con- 70 sheet, e. g. x 50" known to the cenulose tain pigment. Such compositions and colors are plastic art. There are, however, major difiiculties of course known to those skilled in the art.

with these prior processes. The plates or rolls are The composition is colloided and rolled and the very costly; the finish on the plates is very perishsheets from the rolls Welded into a bloc in a 2 able; andinuse they become scratched or marred cake pres I prefer that the block of plastic, 75

in ways which destroy their usefulness. Furtherready for production of decorated sheets in acmore, the finish produced by embossing is frecordance with the invention, have a solvent conquently damaged in the subsequent handling of te t o 8% but e Same may vary from the plastic sheets. Also, the plastic sheets finished to 20%. A p i p i i n m y f r in this Way, when blanked preparatory to placexample, cellulose nitrate 100, plasticizer (e. g. 80 ing over the heel, have a faculty of losing the camphor) 33, softener (e. g. fusel oil) 8, solvent grained eifect and returning to their original ap- (e. g. alcohol) in the specified percentage of the pearance. This occurs particularly during or mixture, and such coloring matter as desired. subsequent to the softening bath treatment which Proceeding to the production of the decorated is used to soften the plastic blank just prior to sheets, the block is severed horizontally into 85 covering the wood heel. The embossing roll is of thin layers, using a knife that in particular aclonger usefulness than the embossing plate (and cordance with the invention is dulled, the depth more costly too) but the embossment produced of the decoration depending upon the degree of by this method is no less perishable than that dullness, the duller the knife the deeper the dec- 5 produced by the plate method. oration. This proper dullness is preferably ob- 9o lhe present invention provides amethod wheretained by first sharpening the blade to a razorby plastic having finishes harmonizing with like edge, as by preliminary sharpening with a grained leathers and textile fabrics and suitable carborundum stone (the ordinary No. 115 s a pfor application in the Wood heel trade may be ening stone used in this art), finishing off the produced in a relatively imperishable form and edge With a natural Stone of eXtreme hardness,

at a relatively low cost, thus making such plastic Arkansas Stone) and then uniformly particularly desirable in this industry. dulling it throughout its len y passing a One object of the invention is to provide a carborundum stone as specified above, fiatwise procedure for the production of plastic sheets dir c ly l n n at right n l to h edge having auniform eife'ct harmonizing with grained of the knife- A8 to the degree of dullness, the 10 leather and textile fabrics throughout the length dulled Cutting ed of he knife y y o and width of the sheet. It has as its further oby, a hickn ss of .0005 inch to a thickness-of ject to provide a decorated sheet with a decoraihoh, depending on the depth of ation tion which, to all practical purposes, is imperishdesired; and also dep on the thickness of able on application to the heel, To these ends the sheet since, obviously, a design should not v and also to improve generally upon methods and e S p as to p entirely through products of the general character indicated, the sheet. (Sheets are ordinarily about .01 5 inch invention consists in the various matters hereinthick.) In cases where a finish which will harafter described and claimed. monize with a very fine grained or weave effect In the accompanying drawing Figure 1 is a is Wanted, it is necessary to dull the knife only to a slight extent. If, however, the coarse grain is desired, it is necessary to dull the knife to a considerable extent.

With the knife in this condition, the block of stock is forced against the dulled edge and the surface of the sheet as it is being removed from the block by the knife is, by the knife, given a rough and irregularly and superficially pitted surface, thereby producing the desired roughened decorative effect over the entire surface of the sheet. It will be understood by those skilled in the art that it is not possible to continue the use of this knife indefinitely and produce a satisfactory sheet. It will be found in following out the intent of this invention that after sheeting a number of sheets it will be necessary to remove the knife and resharpen and re-dull it, before proceeding.

For cutting the block into sheets any suitable machine may be employed such as reciprocating planing orsheeting machine of the character employed in production of pyroxylin plastic. Any

suitable device or devices may be employed for applying heat to the surface of the block if necessary. In practicingmy invention,- assuming that one starts with an empty sheeting machine and places on the base plate thereof a block of plastic, securing the same to the said base plate, it is preferable to then remove the topmost portions of the block, and level the same with a sharp knife. This is to so prepare the block that the top surface of the same shall have a smooth, uniform appearance; The block having been thus prepared, the cutting of the sheets therefrom with a dulled knife in accordance with the invention is proceeded with. The sheets as produced are, of course, decorated on both surfaces. In the drawing the sheet 1 is shown provided with the decorative irregular and superficial pits 2, the sheet being exaggerated in thickness and the are and depth of the pits being also exaggerated.

The sheets produced in accordance with my invention may be seasoned in ways commonly practiced in the cellulose plastic industry. However, I prefer to season the sheets considerably less than one would season sheets produced and sheeted in the regular way, but sufficiently to harden the sheets to fix and preserve the decoration. That is, the residual solvent may be 1.5 percent. This is because the decoration of the sheet produces a non-uniformity in thickness and if the thin portions are too well seasoned there will be a tendency to brittleness in subsequent handling of the sheet. For covering shoe heels the sheets are blanked into individual covers, and the covers applied to the heels in any approved way.

Advantages of the invention are that it produces a plastic sheet with a surface that harmonizes with the grain of leather and with textile fabric weaves used in the shoe industry.

Finishes in accordance with the invention are less costly to produce than are finishes produced by either the embossed plate or roll method. It produces a decorated sheet whose decoration is less perishable than that of sheets produced by other methods. It produces sheets which do not stick together in the blank form in the softening bath customary to use in the wood-heel trade.

In Figure 1 the decoration is greatly exaggerated, while i'nFigure 2 it is illustrated approximately four-times size.

I claim: V

1. The method of producing a decorated sheet comprising passing a separating blade through a body of plastic to divide a sheet therefrom, said blade having its operating edge sufficiently dulled tothereby give the face of the separated sheets a roughened irregularly and superficially pitted surface, as disinguished from a surface with but sheeter lines, the so roughened and pitted surface being thus in itself decorative.

2. The method of producinga decorated cellulosic plastic sheet comprising passing a separating blade through a blockof plastic containing suflicientsolvent to permit such operation, said blade having its operating edge-of a thickness substantially between .0005 and .004 inch, thus to impart to the face of the sheet a roughened irregularly and superficially pitted surface, as distinguished from a surface with mere sheeter lines, the so roughened and pitted surface being thus itself decorative, and seasoning the separated sheet to fix in the surface thereof the decorative irregularities produced by said blade.

ROBERT F. DICKSON. 

